JOSEPH W JOHNSON
Vehicle Board in Pittsburgh, PA

4075037, Feb 21, 1978

May 17, 1976

5/687278

Krishan S. Tarneja - Pittsburgh PA
Joseph E. Johnson - Pittsburgh PA
John Bartko - Pittsburgh PA

Westinghouse Electric Corporation - Pittsburgh PA

H01L 21263

148 15

The recovery charge of power diodes and thyristors is tailored and matched by irradiation through a major surface of the semiconductor body with a given radiation source, preferably of electron radiation, to a dosage corresponding to between about 1. times. 10. sup. 12 and 8. times. 10. sup. 12 electrons per centimeter square with 2 MeV electron radiation. Preferably, the recovery charge of each device of a group of a type of diode or thyristor is first measured, and the group divided into subgroups according to the measured recovery charge of each device. The devices of at least one subgroup is then irradiated with said given radiation source to dosages corresponding to between about 1. times. 10. sup. 12 and 8. times. 10. sup. 12 electrons per centimeter square with 2 MeV electron radiation, and the recovery charge of each irradiated device is again measured to determine the incremental change of recovery charge as a function of irradiation dosage.

4235645, Nov 25, 1980

Dec 15, 1978

5/970045

Joseph E. Johnson - Pittsburgh PA

Westinghouse Electric Corp. - Pittsburgh PA

H01L 2156, H01L 2308

148 15

The preferred embodiment of the invention comprises a glass sealed thyristor and a method for simultaneously constructing a plurality of thyristors and a common semiconductor wafer. The thyristor utilizes a body of semiconductor material with the cathode and base regions extending to one major surface and the anode region extending to the second major surface. A groove is etched in the first surface of the body of semiconductor material to expose the PN junction formed at the interface of the cathode emitter and cathode emitter base regions. A second groove is etched in the second major surface to expose the PN junction formed at the interface of the anode emitter region and the anode emitter base region. Ring shaped glass members are fused to the body of semiconductor material to form seals providing environmental protection for the PN junctions exposed by etching the grooves in the major surfaces of the body of semiconductor material. A plurality of thyristors can be simultaneously constructed on a common semiconductor wafer.

4329707, May 11, 1982

Jul 16, 1980

6/169249

David L. Moore - Jeannette PA
John A. Ostop - Jeannette PA
Joseph E. Johnson - Pittsburgh PA

Westinghouse Electric Corp. - Pittsburgh PA

H01L 2330, H01L 2348, H01L 2944

357 73

A glass disc-shaped thyristor is disclosed. The thyristor comprises a body of semiconductive material having a first emitter region, a first base region, a second base region and a second emitter region therein. A cathode electrode and a gate electrode are affixed to one major surface, and an anode electrode is affixed to the second major surface of the body of semiconductor material. The cathode electrode is disc-shaped and is concentrically positioned with respect to the annular-shaped gate electrode. A ring-shaped glass member is affixed to a first major surface of the body of semiconductive material and to the edges of the cathode and base electrodes to form a seal protecting a PN junction at the interface of the first emitter and base regions. An anode electrode is affixed to the second major surface of the body of semiconductive material. A second annular shaped glass member is affixed to the edge of the body of semiconductive material to form a seal protecting PN junctions formed at the interface of the first and second base regions and at the interface of the second base region with the second emitter region.

4176004, Nov 27, 1979

Aug 21, 1978

5/935429

Joseph E. Johnson - Pittsburgh PA
Edward Dombrowski - Pittsburgh PA

Westinghouse Electric Corp. - Pittsburgh PA

H01L 21306

156643

A method for etching semiconductor fusions to change their electrical characteristic, especially to reduce the firing current of thyristor fusions, to a predetermined desired value is disclosed. The etching is accomplished by subjecting fusions comprised of a body of semiconductor material, for example, silicon, including an anode emitter region therein and an anode electrode affixed thereto, an anode base region, a cathode base region and a gate electrode affixed thereto, and a cathode emitter region having a cathode electrode affixed thereto, to a plasma etchant comprising a mixture of CF. sub. 4 and a carrier gas such for example, nitrogen, for a predetermined time interval. Following this etching cycle the firing current of the fusions is measured. Any fusions having a firing current in excess of the desired value at the end of the first etching cycle are subjected to another etching cycle to further reduce the firing current.

3933527, Jan 20, 1976

Mar 9, 1973

5/339699

Krishan S. Tarneja - Pittsburgh PA
John Bartko - Pittsburgh PA
Joseph E. Johnson - Pittsburgh PA

Westinghouse Electric Corporation - Pittsburgh PA

H01L 21263

148 15

Diodes of a particular type are fine tuned with irradiation to optimize the reverse recovery time while minimizing forward voltage drop and providing more uniform electrical characteristics. The initial and desired minority carrier lifetimes in the anode region of the type are determined as a function of forward voltage drop and reverse recovery time, and the minority carrier radiation damage factor is determined for a desired type of diode and radiation source. The radiation dosage to achieve the desired carrier lifetime with the radiation source is thereafter determined from the function 1/. tau. = 1/. tau. sub. o + K. phi. , where. tau. is the desired minority carrier lifetime,. tau. sub. o is the initial minority carrier lifetime, K is the determined minority carrier radiation damage factor and. phi. is the radiation dosage.

4040877, Aug 9, 1977

Aug 24, 1976

5/717076

Joseph E. Johnson - Churchill PA
John A. Ostop - Greensburg PA

Westinghouse Electric Corporation - Pittsburgh PA

H01L 2122

148187

A plurality of discrete transistor devices are produced on a semiconductor wafer and isolated from one another by moat etching. A passivation layer is then deposited in the moats separating the discrete transistor devices. The semiconductor wafer is then scribed and broken along lines delineated by the moats. The disclosed method permits testing of each discrete transistor device prior to separation from the wafer.

4161746, Jul 17, 1979

Mar 28, 1978

5/891090

Joseph E. Johnson - Churchill PA
John A. Ostop - Greensburg PA
David L. Moore - Jeannette PA

Westinghouse Electric Corp. - Pittsburgh PA

H01L 2302

357 73

A glass sealed semiconductor diode is disclosed. The diode includes a fusion which comprises a body of semiconductor material having a PN junction therein and metal electrodes affixed to opposed major surfaces of the semiconductor body. The fusion is encircled by an annular-shaped glass member with an inner surface of the annular-shaped glass member fused to an edge surface of the fusion to form a protective layer over the PN junction. An annular metallic member encircles the annular glass member with an inner surface thereof fused to an outer surface of the annular glass member.